Education

Research Interests

My research has been on phylogeny and biogeography of woody plants. A phylogeny is the evolutionary history of a species or group of species - its genealogy. Phylogenetic studies help us understand how species are related, the changes that have led to the development of different groups, and the approximate time those changes took place. Tracing the phylogeny of a plant group requires the use of evidence from various disciplines of biology, such as morphology, cytology, chemistry, and molecular biology (the term applied to the use of molecules - protein and DNA - in studying evolutionary relationships). Biogeography is the study of how plant groups got to where they are today; it seeks to learn what may have engendered the origin, dispersal, and extinction of plant groups in different geographic areas.

My focus is on three major groups of plants. The first is the Coniferales, which include pines, spruces, larches, and yews. The goal is to determine whether the Coniferales form a natural group - that is, a closely related biological group - by using both morphological and DNA data to reconstruct the evolutionary history of its members. Currently, researchers are gathering plant material from all around the world to produce a collection that represents all conifer families and genera and 80 percent of the 500 species. This is an ambitious goal with potential long-term benefits for academic communities, the green industry, and the general public. We will establish a framework of evolutionary relationships for major groups within the Coniferales and provide a foundation for further studies at species and population levels. A clear understanding of genetic relationships of species can also guide for cultivar selection and breeding.

The second plant group includes 91 disjunct genera, each with species that occur naturally in both eastern Asia and North America. The goal here is to understand why so many plant genera display a very similar distribution pattern and to learn whether these geographic distributions follow a general pattern of formation. For example, one of the questions is whether North American species of a genus are more closely related to one another than any of them is to eastern Asian species of the genus. Recent studies have shown that there are complex evolutionary patterns in disjunct genera. It is important to investigate the patterns and their correlation with geological times and events. By integrating knowledge from evolutionary history, ecology, and geology, this project will provide a basis for understanding changes in biodiversity over time and for predicting how vegetation will react to ever-increasing human impacts.

The third group consists of economically and horticulturally important plants, especially those that are problematic taxonomically (e.g., Betula, birches; and Acer, maples). Phylogenetic studies will help define natural groups and trace the evolutionary pathways of important features, such as fall foliage in maples and gene duplication and chromosome doubling in some species of birches and maples. Often, plant breeders select cultivars so different from their parents that it is impossible to tell the parentage of cultivars. Nevertheless, DNA can provide unequivocal answers since vegetative selections generally do not change plant DNA constituents and hybrids carry genetic contents from both parents. In addition, Recent work in developmental genetics has identified the genes responsible for regulating certain morphological and physiological traits. By comparing the DNA information in the genes of some of horticultural plants with that of their parents, we can study the correlation between changes in genes and those in the morphology.

Projects

Assembling the Tree of Life of Taxaceae and Araucariaceae - part of the AToL - Gymnosperm project led by Dr. Sarah Mathews and funded by NSF.

Maple phylogeny - Maples (Acer L.) are one of largest woody plant genera in the Northern Hemisphere and are widely distributed in Eurasia and North America. More than 22 sections have been recognized, many of which are natural based on recent molecular studies. However, relationships among sections are basically unknown. This research focuses on the problem and will explore biogeography and character evolution based on a robust phylogeny.

Understand the Lilac Family Tree. Supported by the international lilac society.

Experience

First, let me tell you a bit about myself. I grew up in a small village of central China and went to college to become a teacher. To be a teacher is always my childhood dream since I admired all my teachers from elementary to high schools. After college I decided to go to graduate school to learn more about plants --- diversity, function, and interactions with biotic and abiotic environment. Three years later I realized my childhood dream and became an assistant professor in Henan University. I taught plant ecology, plant geography, and plant systematics and enjoyed working with my colleagues and students in the Geography Department. But I had to move to be in the same city with my wife who was pregnant with our daughter. Then I worked as an assistant professor in the Biology Department of Henan Normal University for five years teaching and doing research in the area of systematic botany and physiological plant ecology. In 1992 I took my first sabbatical and worked in the institute of botany of the Chinese Academy of Sciences in Beijing doing research on Corylopsis (winter-hazel) in the Hamamelidaceae (witch-hazel family). Through reading literature of the plant family, I learned that Dr. Linn Bogle of the University of New Hampshire (UNH) had done much research on Hamamelidaceae, and then contacted him for an opportunity to pursue my Ph.D. there. In August of 1993 I was admitted to UNH's doctorate program in the Department of Plant Biology. My dissertation project initially involved a few genera that are purportedly closely related to Corylopsis, and later evolved into a comprehensive study of Hamamelidaceae using both morphological and molecular data. My dissertation committee included Drs Linn Bogle, Anita Klein, Lee Jahnke, Tom Lee, and Garrett Crow, and they were helpful, insightful, and encouraging. They have made my time in UNH productive, unforgettable, and enjoyable. Of course, I am grateful to UNH for the support. Sponsored by a Putnam postdoctoral fellowship of the Arnold Arboretum, I was able to do my postdoctoral research in 1998 under the supervision of Dr. Michael Donoghue, who was then a Professor of Harvard University Herbaria. Since April 1999, I have worked for the Arnold Arboretum as a botanical taxonomist doing botanical research and supervising the curatorial department, which is responsible for documenting and mapping living collections of the Arboretum. My responsibilities changed to doing full time research as a senior research scientist in 2005. And I have been working on various plant groups to examine their phylogenetics and biogeography, and have enjoyed my tenure at the Arnold Arboretum. However, I do hope to do some teaching as well and have had an adjunct professorship with a few universities in China including Henan Agricultural University, Nanyang Normal College, and Zhejiang University. In July 2009 I joined the faculty of Biology Department of Hope College as a Plant Systematist.

Affiliations

I am a member of American Society of Plant Taxonomists and Botanical Society of America.